1. Field of the Invention
This invention relates to a transmission for a mini shovel car, and more particularly to a worm gear mechanism for a transmission of the type which is designed to drive the left and right crawler drive shafts separately.
2. Description of the Related Art
There have existed no mini shovel cars which are capable of performing excavating operations in a narrow space. In manufacturing a mini shovel car of this sort, considerations need to be given to lower the center of gravity in order to reduce the vehicle body size. A boom which supports a working attachment is mounted on a front portion of the vehicle body while the engine and transmission are mounted on rear portions for balancing the weights in the front and rear portions of the vehicle.
As a means for reducing the body size of such a mini shovel car, it is also conceivable to cut the size of the transmission case. However, the transmissions which are mounted on ordinary conventional shovel cars usually need a large case to accommodate therein complicated mechanisms such as forward/reverse switch mechanism and independent left and right brake mechanisms for driving the left and right crawlers independently to facilitate spin turns of the vehicle.